There have been many instances of school and/or workplace violence. If an assailant has or obtains keys to a school or workplace, then locking the door will not protect the occupants in a room. Even if the door is locked, and the assailant does not have a key, many times an assailant can kick or otherwise knock down a door that is merely held in place by a standard door lock.
Thus there is a need for a device and system that can overcome the above and other disadvantages.